4}; //connect to the column C1-C3 pinouts of the keypad Next is a project example, where the Arduino is instructed to do something based on a correct key (secret number) being entered into the keypad, ...

This circuit uses Microchip’s PIC16C71, an 8-bit microcontroller, to create a digital voltmeter with an LED display and a keypad. To view the application note, click on the URL below.